The present invention relates generally to towing devices and, more particularly, to an adjustable fifth wheel hitch attachment for enhanced maneuverability in limited or tight operating areas.
Fifth wheel hitches for towing a trailer behind a towing vehicle are well known in the art. Typically, fifth wheel hitches include a support frame for mounting the hitch to the towing vehicle. Usually, fifth wheel hitches are mounted within the bed of a pick-up truck. The support frame includes a pair of transverse rails that are bolted to the bed and/or frame of the truck, rail assemblies that are releasably mounted to the transverse rails and upright assemblies mounted to the rail assemblies. A transverse cross bar typically interconnects the upright assemblies, thereby forming a head support for mounting a head assembly by means of a trunnion arrangement allowing for pivotal fore and aft movement. The head assembly includes a jaw assembly operable by means of a control handle and is specifically adapted to releasably engage and hold a kingpin of a towed vehicle.
Conventional fifth wheel trailer hitches typically limit the maneuverability of a towing vehicle at low speeds and in close quarters. In particular, fifth wheel hitches typically center the kingpin of the towed vehicle substantially between the rear wheels and over the rear axle of the towing vehicle. When so mounted, very close clearance is provided between the towed vehicle and portions of the towing vehicle. Under normal towing conditions, the close clearance is sufficient to allow effective operation under speed on the open road. However, the close clearance may hinder maneuverability, especially in situations requiring tight cornering within limited space, such as, for example, the conditions found at campgrounds and some trailer parks.
In order to address the maneuvering shortcomings of conventional fifth wheel trailer hitches, various attempts at adjustable fifth wheel hitches have been made. It has been found that by temporarily moving the hitch assembly rearward in the towing vehicle, clearance between the towing vehicle and the towed vehicle is increased, thereby allowing for greater maneuverability of the towed vehicle. In one adjustable fifth wheel hitch design, the towed vehicle must be detached from the fifth wheel hitch prior to any adjustment of the fifth wheel hitch. The detachment efforts are time consuming and require precise movement of the towing vehicle. The adjustable hitches also typically require more than one person to effect the adjustment of the fifth wheel hitch. Another design utilizes low friction shoes within upright mounting members for movement on parallel guide rails. The uprights are selectively slideable along each guide rail. Each upright includes a hollow cavity for receiving a dual bar latch and a leaf spring for biasing the dual bar latch into a position to lock the uprights against slideable movement. However, the effective weight borne by the low friction shoes tends to cause binding of the shoes such that seizing may occur. The high friction between moving parts prevents easy and smooth adjustment of the fifth wheel trailer hitch. Moreover, the latching mechanism is hidden from view, thereby preventing an operator from confirming engagement of the locking mechanism to lock the adjustable portion against slideable movement.
The present invention is directed to a glider fifth wheel attachment assembly for use with fifth wheel towing assemblies attached to motor vehicles. The glider fifth wheel attachment assembly includes a support frame including a pair of spaced guide rails and a pair of upright assemblies attached to the guide rails. Each upright assembly includes a lower sleeve portion for receiving a respective guide rail, an intermediate housing portion vertically above the sleeve portion, and an upper mounting portion vertically above the housing portion. A head assembly may be adjustably mounted between respective mounting portions of the upright assemblies. One roller is positioned within each housing portion of the upright assemblies such that the roller contacts an upper surface of an upper guide rail. The glider fifth wheel attachment assembly further includes a latching assembly for releasably locking the glider fifth wheel attachment assembly between a first and a second towing position.
In a first embodiment, each housing portion includes two spaced rollers contacting the upper surface of the respective guide rails. In a more preferred embodiment, the latching assembly further includes a generally L-shaped bar, wherein a first end of the bar extends through aligned apertures in the housing portions. At least one latch pin is mounted parallel to and laterally spaced from the first end adjacent at least one of the upright assemblies. The latch pin is received in one of a plurality of apertures formed in the guide rails, wherein the plurality of apertures correspond to the respective first and second positions. Moreover, the latching mechanism is preferably biased to a latched position in either the first or second position by means of a compression spring located along the first end of the latching bar. The housing portions may further include at least one strap parallel to an axis of rotation of the rollers, and closely adjacent thereto.
In a second embodiment, fore and aft movement of the glider fifth wheel hitch may be automatically accomplished without requiring that the vehicle operator exit the vehicle. Instead of a manually releasable latch mechanism, the fifth wheel hitch includes an automatic adjustment device adapted to selectively move the fifth wheel hitch fore and aft in response to remote operator input.
The one method, an electric motor is mounted to a generally T-shaped support brace mounted between the upright assemblies. Distal ends of the upper, transverse portion of the T-shaped brace are respectively attached to each of the pair of upright assemblies. The center portion of the T-brace includes both an outer and inner tubular member, where the inner tubular member is telescopically mounted within the outer member. A threaded nut is concentrically fixed in place within the inner tubular member, while a threaded rod extends concentrically within the outer tubular member. A first end of the threaded rod threadedly engages within the nut, while a second end of the rod is attached directly to a gear reduction box and the electric motor, both of which are attached directly to the vehicle frame. To move the fifth wheel hitch, the vehicle operator may selectively actuate the motor to rotate the threaded rod on its axis. As the rod turns, it is either drawn into or removed from the fixed nut (depending upon the direction of rotation), thereby forcing the inner tubular member to telescope into or be forced out of the outer tubular member. In this way, the length of the center portion of the T-shaped brace is shortened or lengthened, thereby causing the attached fifth wheel hitch to move fore or aft as desired.
The glider fifth wheel attachment assembly of the present invention allows adjustment of the fifth wheel hitch assembly using rollers. As a result, the fifth wheel trailer hitch is allowed to roll fore and aft, while the towed vehicle remains coupled to a towing vehicle. Advantageously, the glider fifth wheel attachment assembly rolls, rather than slides. Binding between the fifth wheel trailer hitch and the guide rails due to uneven rolling or excessive friction is therefore entirely eliminated. In the first embodiment, the latching mechanism is visible outside of the upright assemblies so that an end user may positively identify when the glider fifth wheel attachment assembly is locked in either a first or a second position. Moreover, the latching mechanism is preferably biased to a latched position in either the first or second position by means of a compression spring located on a first end of the latching bar. In this way, shortcomings of prior art adjustable fifth wheel hitch assemblies are overcome.
The automatic version of the fifth wheel hitch allows continuous adjustment fore or aft, and does not require that the vehicle operator exit the vehicle to release or engage the locking mechanism. Importantly, the towed vehicle may be towed with the hitch set at any point within the distance of travel of the adjustable device. Additionally, adjustment of the towed vehicle does not require any movement of the towing vehicle.